Distribution Integration

The goal of NREL's distribution integration research is to tackle the challenges facing
the widespread integration of distributed energy resources while maintaining the safe,
efficient, and cost-effective operation of the distribution system.

NREL's research on the integration of distributed energy resources, such as PV, began
more than a decade ago and has included numerous high-impact projects. These projects
have spanned the research spectrum from comprehensive projects in which we partnered
with utilities to develop best practices for solar integration, to developing technical
screening methods to “fast track” the interconnection of distributed energy resources,
to evaluating the value of energy storage systems in the distribution system.

Projects

This project addresses the use of high penetrations of PV in islanded microgrids to
increase overall system efficiency, decrease fuel costs, and maintain resiliency of
the overall system. A real microgrid scenario with a high penetration of PV is being
tested in NREL's Energy Systems Integration Facility. Multiple control cases for firming PV using storage tested.

In this project, NREL is providing research and testing support to San Diego Gas &
Electric, including:

The Microgrid Cost Study is focused on identifying the costs of components, integration,
and installation of existing U.S. microgrids and project cost improvements and technical
accelerators over the next five years and beyond. This information can be used to
develop research and development agendas for next-generation microgrids that provide
cost-effective, reliable, and clean energy solutions. This project will provide insight,
transparency, and standardization in the reporting of microgrid costs and identify
market segment differences for future cost reductions across microgrid applications

Quasi-static time-series (QSTS) analysis of the distribution system is valuable when
studying the anticipated impacts of interconnecting new PV systems. As the number
of PV systems on distribution systems increases, the application of relatively simple,
conservative assumptions or proxies for anticipated PV impacts becomes ever more unrealistic
and potentially limits the amount of PV allowed to interconnect. However, the data
and time required to complete QSTS analysis are formidable barriers to its everyday
use in utility-relevant PV interconnection studies. This project seeks to eliminate
these barriers by decreasing the time required to complete a yearlong 1-second-resolution
QSTS study from 50 hours to 5 minutes and developing load and PV models that are easy
to use with existing lower-resolution utility and environmental data.

NREL's PREconfiguring and Controlling Inverter SEt-points (PRECISE™) tool is a standalone system that enables autonomous operation of distributed energy resources
by leveraging advanced inverters modes. Developed in partnership with Sacramento Municipal
Utility District, PRECISE helps utilities in the United States and beyond by identifying
optimal inverter modes and settings to maximize the cost-effective use of installed
solar systems. The PRECISE platform has a quasi-static time series capability, combined
with mathematical optimization, and three modules that operate in a specific order
to identify optimal advanced inverter modes. The distribution power-flow module provides
distribution operators an interface to view the network topology, geographical location
of the requested PV system, and other existing PV systems.